This invention relates generally to vehicle inflatable restraints and, more particularly, to the mounting of a cover door for an inflatable air bag installed in an instrument panel.
Many passenger vehicles manufactured today are equipped with supplemental inflatable restraints for the vehicle driver, commonly known as air bags. An increasing number of vehicles are also being equipped with an air bag for the front seat passenger. This air bag is part of an air bag assembly which includes an inflator and a reaction canister located in a recess in the vehicle instrument panel. The air bag deploys through an opening in the instrument panel.
The instrument panel normally comprises a metal support structure covered by a panel comprising a rigid substrate on which is mounted a resilient foam pad having a flexible plastic decorative outer skin covering. The instrument panel support mounts the air bag assembly in the recess and incorporates a cover door which closes the deployment opening.
In some vehicles the air bag door comprises a foam pad and skin which are an integral portion of the panel. A supporting substrate is cut out to define the door shape. Upon deployment, the inflating air bag forces a door-shaped cutter to rip through the panel foam and skin to release the inflating air bag.
In other vehicles the skin includes a tear seam line of weakened panel material along three sides of the door. This tear seam is fractured by the inflating air bag so that the door swings open about its fourth side, which functions as a hinge, to enable the air bag to properly deploy.
In yet other vehicles this cover door is a separate rectangular panel that is flush mounted in a rectangular opening in the surrounding panel area so that it can be opened and completely removed by the deploying air bag upon inflation. This type of door is usually attached to the instrument panel at its forward edge by a hinge or by a tether to cause the door to swing open about this attachment out of the path of the deploying air bag.
It is essential that this type of door be releasably installed in the panel opening so that it completely separates and moves out of the way of the deploying air bag. However, the door must remain attached to the instrument panel upon opening so that it does not become a hazard to occupant safety.
It is desirable that the door be releasably secured by retaining means which exert a force that is sufficiently great to resist the door being pried open so that the integrity of the air bag installation is preserved. This force must also be sufficiently small to assure that the door is released by the deploying air bag.
It is also desirable that the door be maintained releasably installed by retaining means which reliably remain attached to the instrument panel upon opening. It is important that the retaining means do not become detached during air bag deployment or encroach upon the path of the air bag as it deploys.